NF-Y transcription factors are likely found in all eukaryotes and have roles in the regulation of diverse genes (McNabb et al., 1995; Edwards et al., 1998; Maity and de Crombrugghe, 1998; Mantovani, 1999). In mammals, where their biochemistry is well described, the NF-Y transcription factor complex is composed of three unique subunits: NF-YA, NF-YB, and NF-YC. Assembly of the NF-Y heterotrimer in mammals follows a strict, stepwise pattern (Sinha et al., 1995, 1996). Initially, a heterodimer is formed in the cytoplasm between the subunits NF-YB and NF-YC. This dimer then translocates to the nucleus, where the third subunit, NF-YA, is recruited to generate the mature, heterotrimeric NF-Y transcription factor (Frontini et al., 2004; Kahle et al., 2005). Mature NF-Y binds promoters with the core pentamer nucleotide sequence CCAAT, and this can result in either positive or negative transcriptional regulation(Peng and Jahroudi, 2002, 2003; Ceribelli et al., 2008).